Document Gm3mm0wXYYw8n6zbjv6ao6kD4

December 15* 1952 Dr, El3ton L. Belknap 251 V.r# V|iscons in Avenue Milwaukee, 'Wisconsin Dear Doctor Belknap* I have looked into the Lederer method for lead determinations referred to in your letter of November 28th and in my opinion and in that of my assistant Mr# Thamann, it is hardly sensitive enough to employ in the case of the urine# Since in my opinion the urinary findings are commonly more important than the [results in the faeces, it would seem to rao that this method could not be used satisfactorily# According to Mr, Thamann, quantities as high as .2 of a milligram might be lost entirely, while with the use of the H2S generator described, the samples would almost certainly be contaminated with iron invariable amounts. Such iron precipitated as FeS would be estimated as lead. Sinee the horo would be Inconstant, the method could hardly be regarded as satisfactory. I see no reason why we can not cooperate with your laboratory by giving your technician such assistance a3 you suggest# If you will let me know what you wish to do, weTshall be pleased to make it possible for her to work with us for a time. i 1 i Cordially yours. BAKjIS